使用Java如何监控并输出日志文件

package com.bill99.seashell.domain.svr;  import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.Writer; import java.text.SimpleDateFormat; import java.util.Date; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit;  public class LogSvr {    private SimpleDateFormat dateFormat =   new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");     public void logMsg(File logFile,String mesInfo) throws IOException{   if(logFile == null) {    throw new IllegalStateException("logFile can not be null!");   }   Writer txtWriter = new FileWriter(logFile,true);   txtWriter.write(dateFormat.format(new Date()) +"\t"+mesInfo+"\n");   txtWriter.flush();  }    public static void main(String[] args) throws Exception{      final LogSvr logSvr = new LogSvr();   final File tmpLogFile = new File("mock.log");   if(!tmpLogFile.exists()) {    tmpLogFile.createNewFile();   }   //启动一个线程每5秒钟向日志文件写一次数据   ScheduledExecutorService exec =    Executors.newScheduledThreadPool(1);   exec.scheduleWithFixedDelay(new Runnable(){    public void run() {     try {      logSvr.logMsg(tmpLogFile, " 99bill test !");     } catch (IOException e) {      throw new RuntimeException(e);     }    }   }, 0, 5, TimeUnit.SECONDS);  } }